Long-term outcome of immunotherapy for patients with refractory pancreatic cancer

Background: Pancreatic cancer is one of the most fatal human cancers, with a 5-year survival rate of <5%. Although new chemotherapies have been used for pancreatic cancer, the outcome is still poor. Here, we retrospectively analyzed the outcome of immunotherapy in pancreatic cancer patients and revealed the potential of immunotherapy in advanced pancreatic cancer treatment. Patients and Methods: Seventeen pancreatic cancer patients underwent immunotherapy in the Kyushu University and the Yakuin CA Clinic. Six patients had postoperative recurrence, 11 were diagnosed as inoperable because of metastasis, 16 had prior chemotherapy and developed chemotherapy-resistant cancers, while 1 patient had no prior chemotherapy for recurrent cancer after surgical resection because of leukopenia. Immunotherapy was combined with chemotherapy in 11 patients and without chemotherapy in 6 patients. Immunotherapy was classified into two groups; combined dendritic cell (DC) vaccination and intravenous or peritoneal injection of activated lymphocytes (DC vaccine therapy), or injection of lymphokine- activated killer lymphocytes (LAK) alone (LAK therapy). Results: Immunotherapy of refractory pancreatic cancer resulted in a median survival of 9 months. Peritoneal metastasis tended to shorten the survival period. Combination immunotherapy and chemotherapy showed no obvious difference as compared to immunotherapy alone. DC vaccine therapy conferred a significantly better survival period than LAK alone. Conclusion: Our results suggest that immunotherapy utilizing DC vaccination may prolong the survival of refractory pancreatic cancer patients.